Why Infant Formula Is No Match For Breast Milk To Protect Infants From Infection and Illness

The benefits of breast milk have long been appreciated and regarded as liquid gold, but now scientists at Duke University Medical Center have described exactly what unique properties make a mother's milk better than infant formula in protecting infants from infections and illnesses.
The finding, published in the August issue of the journal Current Nutrition & Food Science, explains how breast milk, but not infant formula, fosters colonies of microbiotic flora in a newborn's intestinal tract that aid nutrient absorption and immune system development.

Human milk oligosaccharides, or HMO, produce short-chain fatty acids that feed a beneficial microbial population in the infant gut. Not only that, the bacterial composition adjusts as the baby grows older and its needs change. HMO is virtually absent from infant formula.

Breast milk is the perfect food for baby, with numerous advantages over baby formula, especially in the first four months or so. Here's why:

It's always available.

It's free.

It contains active infection-fighting white blood cells and natural chemicals that give increased protection against infections in the first months, when these can be the most serious.

It can help prevent SIDS, sudden infant death syndrome, according to the American Academy of Pediatrics.

It contains the perfect proportion of nutrients that your baby needs, including protein, carbohydrates, fat, and calcium.

It is easily digestible.

It may protect against allergies and asthma in the future.

It may decrease a baby's risk of obesity in the future.

It may contain some fatty acids that promote brain development.

Breastfeeding can help new mothers lose weight more easily.

"This study is the first we know of that examines the effects of infant nutrition on the way that bacteria grow, providing insight to the mechanisms underlying the benefits of breast feeding over formula feeding for newborns," said William Parker, PhD, associate professor of surgery at Duke and senior author of the study. "Only breast milk appears to promote a healthy colonization of beneficial biofilms, and these insights suggest there may be potential approaches for developing substitutes that more closely mimic those benefits in cases where breast milk cannot be provided."

Earlier studies have shown that breast milk lowers the incidence of diarrhea, influenza and respiratory infections during infancy, while protecting against the later development of allergies, type 1 diabetes, multiple sclerosis and other illnesses. As scientists have learned more about the role intestinal flora plays in health, they have gained appreciation for how an infant's early diet can affect this beneficial microbial universe.

In their study, the Duke researchers grew bacteria in samples of infant formulas, cow's milk and breast milk. For the infant formula, the researchers used three brands each of popular milk- and soy-based products, and they purchased whole milk from the grocery store. Breast milk was donated and processed to separate different components, including proteins, fats and carbohydrates. They also tested a purified form of an antibody called secretory immunoglobulin A (SIgA), which is abundant in breast milk and helps establish an infant's immune system.

The infant formulas, the milk products and the SIgA were incubated with two strains of E. coli bacteria -- necessary early inhabitants of the gut that are helpful cousins to the dangerous organisms associated with food poisoning.

Within minutes, the bacteria began multiplying in all of the specimens, but there was an immediate difference in the way the bacteria grew. In the breast milk, bacteria stuck together to form biofilms -- thin, adherent layers of bacteria that serve as a shield against pathogens and infections. Bacteria in the infant formula and cow's milk proliferated wildly, but it grew as individual organisms that did not aggregate to form a protective barrier. The bacteria in SIgA had mixed results, suggesting that this antibody by itself isn't enough to trigger the beneficial biofilm formation.

"Knowing how breast milk conveys its benefits could help in the development of infant formulas that better mimic nature," Parker said. "This could have a long-lasting effect on the health of infants who, for many reasons, may not get mother's milk."

Parker said additional studies should explore why human whey has the clumping effect on the bacteria, and whether it has a similar effect on strains of bacteria other than E. coli.

"This study adds even more weight to an already large body of evidence that breast milk is the most nutritious way to feed a baby whenever possible," said Gabriela M. Maradiaga Panayotti, M.D., co-director of the newborn nursery for Duke Children's and Duke Primary Care. "We know that babies who receive breast milk have better outcomes in many ways, and mother who breast feed also have improved health outcomes, including decreased risks of cancer. Whenever possible, promoting breast feeding is the absolute best option for mom and baby."

A simple comparison of breast milk over formula shows its superiority:

Fat is the most important nutrient in breastmilk; the absence of cholesterol and DHA, vital nutrients for growing brains and bodies, may predispose a child to adult heart and central nervous system diseases. Leftover, unabsorbed fat accounts for unpleasant smelling stools in formula-fed babies.

-Not absorbed as well
-Iron is 5 to 10 percent absorbed
-Contains less selenium (an antioxidant)

Vitamins and minerals in breast milk enjoy a higher bioavailability-that is, a greater percentage is absorbed. To compensate, more is added to formula, which makes it harder to digest.

Enzymes Hormones

-Rich in digestive enzymes, such as lipase and amylase
-Rich in many hormones: thyroid, prolactin, oxytocin, and more than fifteen others
-Varies with mother's diet

-Processing kills digestive enzymes
-Processing kills hormones, which are not human to begin with
-Always tastes the same

Digestive enzymes promote intestinal health. Hormones contribute to the overall biochemical balance and well- being of baby.
By taking on the flavor of mother's diet, breastmilk shapes the tastes of the child to family foods.

Cost

-Around $600 a year in extra food for mother

-Around $1,200 a year
-Up to $2,500 a year for hypoallergenic formulas
-Cost for bottles and other supplies
-Lost income when baby is ill

Natasha Longo has a master's degree in nutrition and is a certified fitness and nutritional counselor. She has consulted on public health policy and procurement in Canada, Australia, Spain, Ireland, England and Germany.